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COMMENTS:
Note 1: More heat needed than power.
An approximate cost of making the huge reduction in the energy assumed by policy makers is likely to be at least of £30,000 per house in Britain where the existing housing stock is approximately 30 million. When multiplied together the cost of this assumption amounts to roughly £1 trillion, and that does not include domestic hot water. See also the CHP page for more about space heating.
Even in summer a home requires roughly the same amount of energy to provide domestic hot water as it consumes as electricity.
The K-H concept recognises that the energy economy is heat rather than power constrained. Even at times when air-conditioning is necessary it is easy to show that running it from fuel cells is more efficient than from thermal or nuclear power stations.
Note 2: A clear vision for a sustainable energy economy
Other approaches take a mix of technologies in incremental steps with no clear vision for a final infrastructure, but this concept offers a clear picture for a final efficient and cost effective infrastructure.
It demonstrates a hydrogen economy in its purest form. It is also far simpler and potentially far lower cost than current energy and infrastructure or extending the current infrastructure. Almost the whole gross (HHV) primary energy is put to use as heat and power. The end user can use the heat for domestic hot water and space heating, and can use the power either as power or, through resistive heating, as additional heat. Transmission losses are almost zero compared to 7% or more for electricity. The losses in converting primary energy (biomass or renewable electricity) to hydrogen are much lower than converting biomass to electricity.
Experts have calculated the learning curve for the price of fuel cells and shown that in volume their price would be less than a modern condensing boiler. No boiler would be needed. The electricity grid is far more expensive to build and maintain than delivery of energy in gas pipes. The electricity grid is not even needed.
The conversion of fuel to hydrogen is also much more efficient and also less costly than to electricity. Indeed, an Integrated gas combined cycle (IGCC) power station with carbon capture and storage consists of a gas fired power station running on hydrogen from a preceding gasifier producing hydrogen from a hydrocarbon fuel. When biomass is used instead of a fossil fuel this process becomes carbon negative reversing climate change. Only this first hydrogen production stage is needed. The gas fired power station becomes redundant. There are therefore great overall improvements in both cost and efficiency compared to current practice.
The concept could be improved in some ways, but this would introduce some extra costs. For example:
* a user might use a heat pump to provide more heat than from simple resistive heating
* a few neighbouring premises might be electrically connected to improve continuity and diversity, for example during servicing.
* a user might add solar panels (PV or thermal or both)
The concept has a few weaknesses:
* The energy that can be stored in the natural gas infrastructure is much less for hydrogen than for natural gas, though biomass can be stockpiled as an additional store of energy
* Biomass will have to be not only collected, but also transported to the regional hydrogen factories
* Electricity from wind, sea and sun is better carried to end users as electricity than converted to hydrogen. Even with efficient electrolysis only half the original electrical energy is recoverable as electricity. Therefore electrolysis is only justified when electricity is in surplus.
* The bigger question is whether investment in renewables is wise or necessary when K-H shows that energy from biomass in a hydrogen economy would be far cheaper and just as sustainable.
Note 3 (Heat and its units)
The use of mechanical measures of energy are now commonly used for heat. These measures are joules (J) and huge Exajoules EJ (10^18 Joules), and kilowatt-hours (kWh) and huge Gigawatt-hours. These are ultimately defined in terms of our absolute standards of length, mass and time. Energy is interchangeable between these forms: mechanical, electrical and radiation, with no loss except for friction, resistance and the dissipation of radiation (e.g. solar radiation) in which case the loss of energy in these forms becomes heat energy which raises temperature. All forms of energy can therefore be measured in Joules or kWh by comparing their heating value. The second law of thermodynamics however states that it is much more difficult to recover these other forms of energy from heat.
Chemical reactions either release heat (exothermic) or absorb heat (endothermic). A chemical engineer tries to minimise the external heat he requires and put any excess heat to good use. Although he thinks in terms of heat energy he measures it in Joules or kWh . He will try to minimise the escape of heat into the environment.
Note 4: UK energy & distribution costs
Electrical engineers would say that the picture of 600 MW gas versus electricity transmission is unfair because the second law of thermodynamics clearly shows that energy in in electrical form is more valuable. K-H however argues that since we live in a heat constrained economy both forms have equal value. Then his picture is valid. His costs, which are 2012 German figures, then strengthen his argument.
The retail bill from my UK supplier of gas and electricity (in 2015) shows that for an average UK house the costs of delivery (regulated by Ofgem) are 1.0 p/kWh for gas and 3.4 p/kWh for electricity. The cost for gas is very similar to the 1 cent cost in Germany, but the cost for electricity in UK is much lower than 11 cent cost in Germany. All figures exclude tax, profit and environmental levies, etc. (In a private conversation with a long experienced UK gas engineer I was told that historically electricity costs seven times as much as gas to distribute. Taking account of currency difference this would come closer to the K-H figure of 11 cents.) I am never confident in the validity of such figures. For instance, accountants and tax authorities can apply varying rates of depreciation to the cost of infrastructure.
My retail bill also shows the UK wholesale costs of gas are 2.1 p/kWh and 5.8 p/kWh for electricity. For Germany in 2012 K-H quotes: 3 cent/kWh for natural gas (see H2-Production) and 4 cent/kWh for electricity.
The low cost of natural gas in UK makes it more economic to produce hydrogen from natural gas than from biomass. This low price of natural gas in the UK is due to the plentiful supply it has enjoyed from the North Sea. Those supplies however are now declining and the UK is having to import natural gas. It is also anxious to develop fracking as a source of gas. The UK will therefore be forced to pay world market prices as does Germany. The drop in oil and gas prices 2014-15 is unlikely to be permanent. Nor can any of these sources of fossil gas be carbon neutral (or carbon negative with carbon capture).
Note 5: All-Electric versus Hydrogen Economy
Policy makers and public alike tend to think in terms of an all-electric future, but opinions vary as to how much more electricity infrastructure will be necessary. Some argue that with greater efficiency in its use such as heat pumps, LED lighting, passivhaus buildings, and electric transport that less might be required and the old gas infrastructure dismantled.
K-H however points out that currently only 17% of the primary energy used by a home is for power. Therefore nearly six times as much primary energy is needed for heat than power. Similar considerations apply to other buildings, etc. Even transport needs heat and light for example: An electric train needs as much power to provide comfort as to propel it and the range of battery powered cars nearly halves in city driving in winter. From these figures it seems likely that K-H is right.
There is a second weakness in assuming an all-electric future from sun, sea and wind can be economical. Onshore wind typically produces only about 22% of its design power over a year, and offshore about 43%. These imply that the wind capacity that would have to be installed would have to be 2.5 to 4.5 times the nameplate capacity. It is for these reasons that policy makers justify nuclear capacity. All these require a further source of on-demand electricity from fuels or pumped storage. Besides these primary energy sources all must be interconnected at far greater expense than for gas which already reaches 83% of British households.
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